Two deputies were taken to the hospital after being exposed to an unknown substance during a drug-related traffic stop Monday night that halted traffic for several hours in Brookfield.

One of the deputies was administered Narcan at the scene and both were treated at a local hospital as a precautionary measure.

Both were later released.

The traffic stop closed a portion of I-94 westbound on Monday and two men were arrested at about 9:08 p.m. near South Calhoun Road.

The driver of the car was arrested for OWI and drug-related charges. The passenger was arrested on drug-related charges.

According to police, the deputies were exposed to the unknown substance during a search of the vehicle.

Wisconsin State Patrol, city of Brookfield Fire Department, Waukesha County Metropolitan Drug Unit and Wisconsin Department of Criminal Investigations (DCI) were on the scene to assist in the investigation.

This matter remains under investigation by the Waukesha County Sheriff’s Department.